US3674637A - Spacer grid for nuclear reactor fuel element assembly - Google Patents

Spacer grid for nuclear reactor fuel element assembly Download PDF

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Publication number
US3674637A
US3674637A US835117A US3674637DA US3674637A US 3674637 A US3674637 A US 3674637A US 835117 A US835117 A US 835117A US 3674637D A US3674637D A US 3674637DA US 3674637 A US3674637 A US 3674637A
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US
United States
Prior art keywords
sheet metal
grid
spacer grid
nuclear reactor
spacer
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Expired - Lifetime
Application number
US835117A
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English (en)
Inventor
Jacques Delafosse
Jean-Luc Viaud
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Commissariat a lEnergie Atomique et aux Energies Alternatives CEA
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Commissariat a lEnergie Atomique CEA
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Publication of US3674637A publication Critical patent/US3674637A/en
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Expired - Lifetime legal-status Critical Current

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    • G—PHYSICS
    • G21—NUCLEAR PHYSICS; NUCLEAR ENGINEERING
    • G21C—NUCLEAR REACTORS
    • G21C3/00—Reactor fuel elements and their assemblies; Selection of substances for use as reactor fuel elements
    • G21C3/30—Assemblies of a number of fuel elements in the form of a rigid unit
    • G21C3/32—Bundles of parallel pin-, rod-, or tube-shaped fuel elements
    • G21C3/34—Spacer grids
    • G21C3/356—Spacer grids being provided with fuel element supporting members
    • G21C3/3563—Supporting members formed only by deformations in the strips
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
    • Y02E—REDUCTION OF GREENHOUSE GAS [GHG] EMISSIONS, RELATED TO ENERGY GENERATION, TRANSMISSION OR DISTRIBUTION
    • Y02E30/00—Energy generation of nuclear origin
    • Y02E30/30—Nuclear fission reactors

Definitions

  • the present invention is concerned with a spacer grid for a nuclear reactor fuel element assembly and particularly an assembly comprising a bundle of rods formed of fissile or fertile material, said rods being supported at each end by a grid and maintained at uniform intervals by means of other grids or braces, the intended function of said grids and braces being to ensure uniform spacing between said fuel rods and to prevent deformation of these latter.
  • the aim of this invention is to circumvent the disadvantages referred to above by providing a spacer grid which has a sufiiciently large number of points of contact with the fuel rods as well as low resistance to coolant flow.
  • This invention is in fact directed to a spacer grid for a fuel element assembly in which a bundle of rods formed of fissile or fertile material is braced by spacer grids each comprising within a frame a lattice of interassembled sheet metal members which define compartments having a square section, said spacer grid being characterized in that it is made up of cut-out sheet metal members each comprising two parallel rectilinear ribbon elements, narrow corrugated strips forming a number of projections on each side of the sheet metal member and defining openings between the ribbon elements, and slits forming interruptions in one of the ribbon elements in the center-line of each opening so as to permit the insertion of the continuous ribbon element of another sheet metal member, all said sheet metal members being attached at the extremities thereof to similar sheet metal members which form the sides of the outer frame.
  • Each fuel rod is thus maintained in four different directions uniformly distributed around its periphery and at a number of points located at dilferent heights along its length, that is to say at a relatively large number of points.
  • Said sheet metal members are fabricated by punching, die-stamping and bending which are carried out successively and in continuous operation, thereby minimizing their cost price. Furthermore, the assembly operation is both simple and accurate. Fabrication can therefore be readily carried out on a large scale at low cost.
  • FIG. 1 shows diagrammatically and in perspective a fragmentary view of a spacer grid in accordance with the invention. However, only a part of said grid is visible in this figure since the entire grid is of similar construction;
  • FIG. 2 is an exploded view on a larger scale showing the interassembly of cut-out sheet metal members which form the spacer grid of FIG. 1;
  • FIG. 3 is a sectional view on a smaller scale and taken along line II of FIG. 2;
  • FIG. 4 is a partial and fragmentary diagrammatic view in perspective and on a larger scale showing the assembly of spacer grids on one fuel element.
  • the spacer grid which is intended to support the rods of fissile or fertile material of a nuclear reactor fuel assembly is constituted as shown in FIG. 1 by a square lattice of metallis strips 2, 4 disposed at right angles and defining compartments 6 which have a substantially square section. Said metallic strips 2, 4 are secured at each end within a frame 8 formed by four sheet metal members which are similar to the strips 2 and 4 and welded to each other. A rod 7 of fissile or fertile material can thus be placed in each compartment 6 in order to be braced by the compartment walls.
  • openings 10 of relatively large size with respect to the surface area of the sheet metal member itself are cut-out in the central portion of each member 2, 4.
  • Said openings are all of equal size, uniformly spaced and separated by narrow strips 12 of corrugated or wavy shape which form as shown by Way of example in FIG. 2 three bosses 13, 14 and 15 between the two adjacent openings 10.
  • the central boss 14 projects on one side of the sheet metal member Whilst the bosses 13 and 15 project on the other side.
  • each ribbon element On each side of said corrugated strip 12, the top and bottom full portions of the sheet metal member 2 or 4 form two rectilinear ribbon elements 2a, 2b or 4a, 4b, each ribbon element being also provided with a boss 16 which is directed towards the same side as the bosses 13 and 15 but is of greater height.
  • the top ribbon element 2a is interrupted by a slit 18 whereas, in the case of the sheet metal members 4 which are perpendicular to the members 2, the ribbon element 4b is also interrupted by a slit 20 located at the bottom of each opening 10.
  • the ribbon elements 2a and 4b are thus interrupted at uniform intervals.
  • the members 2 and 4 can be interassembled by sliding them together, the walls of the slits 20 being thus placed on each side of the member 2 beneath the opening 10 whilst the top portion of the member 4 is maintained within the slit 18 of the member 2.
  • the sheet metal members which have thus been interassembled can readily be joined by electron beam welding, local brazing, resistance welding or any other suitable means in order that said members should be rigidly coupled together and that any relative displacement of these latter should thus be prevented.
  • Each compartment 6 is limited on each of its four sides by a portion of sheet metal member, the central part of which is formed by a corrugated strip 12 whilst the corners of each compartment are cut away since they are formed by the junction of the full portions located between the slits 18 or 20 at the level of two openings 10.
  • each fuel rod 7 is in contact on the one hand with the boss 14 of a sheet metal member 4 and the bosses 16 of the adjacent member 4 and on the other hand with the boss 14 of a sheet metal member 2 and the bosses 16 of the adjacent member 2.
  • the fuel rod is thus maintained at points which are distributed along four uniformly spaced generator-lines and at several points of the height of said rod.
  • the flexibility imparted to the corrugated strip 12 by the bosses 13 and 15 serves to absorb deformations While permitting the liquid coolant to flow even between said contacting strip 12 and the fuel rod.
  • the sheet metal members 2 as well as the members 4 are each secured at one end to one side of the frame 8 which is also made up of cut-out sheet metal members in which the cut-out portions or openings 10 are limited by corrugated strips 12 of small width and ribbon elements in which are formed bosses 16.
  • the sheet metal members of the frame are provided with extensions both at the top and at the bottom in the form of teeth 24 which have the shape of rounded triangles and are slightly inclined toward the center of the spacer grid.
  • teeth 24 which have the shape of rounded triangles and are slightly inclined toward the center of the spacer grid.
  • Each sheet metal member 2 and 4 is fabricated in a series of operations such as punching, die-stamping and bending which are performed at low cost and which can readily be carried out in large-scale production.
  • Each flexible corrugated strip or spring which is applied against the fuel rod has a degree of independence which facilitates constructional assembly and prevents deformations during fabrication.
  • the cut-out sheet metal members which are thus obtained are then assembled by interengagement of the two members and accurate spot-welding by electron beam process, plasma-torch welding or the like, there being no need to carry out any operation for the purpose of correcting deformations.
  • the assembly is thus particularly simple and the spacer grid is inexpensive to produce.
  • guide tubes 21 can be placed in a number of compartments 6 and secured in the corners of these latter by means of radial fins 22 (as shown in FIG. 1) which are either brazed, welded or secured to the sheet metal members by any suitable means.
  • each spacer grid is designed to support a spacer tube 28 which serves both as a tie between said grid and the adjacent grid and as a passageway for a control rod guide tube 30.
  • Each extremity of said spacer tube 28 terminates in an end-fitting 32 which is secured to the sheet metal members 2 and 4 by welding, brazing or the like so that said members form a compartment 6 of the spacer grid externally of said end-fitting.
  • the grids are thus supported at a predetermined distance and joined to each other as well as to the top and bottom support plates 34 of the fuel element assembly.
  • the sheet metal members may be fabricated, for example, from a nickel-iron-chromium alloy such as the alby known as Inconel 718, from stainless steel, from a zirconium alloy or from any like metal.
  • a spacer grid for a nuclear reactor fuel elementassembly in which a bundle of rods of fissile or fertile material are mounted comprising a frame, a lattice of interassembled sheet metal members in said frame which define compartments having a square section, said sheet metal members each comprising two parallel upper and lower rectilinear ribbon elements, narrow corrugated strips between said upper and lower ribbon elements having a number of projections on each side of said sheet metal members, generally rectangular openings defined by said ribbon element and by said strips, and slits in one of the ribbon elements in the center-line of each opening for insertion of the continuous ribbon element of another sheet metal member, all said sheet metal members being attached at the extremities thereof to similar sheet metal members which form the sides of the outer frame, each narrow strip having bottom and top bosses extending in the same direction and a corrugated portion forming at least one substantial projection in the direction opposite to that of said bosses.
  • a spacer grid in accordance with claim 1 said grid including guide tubes secured by radial fins in a number of compartments of said spacer grid.
  • a nuclear reactor fuel element assembly comprising bundles of fuel rods supported by a plurality of spacer grids in accordance with claim 3, said spacer grids being secured to each other and to the top and bottom support plates of the fuel element assembly by spacer tubes.

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  • Physics & Mathematics (AREA)
  • Engineering & Computer Science (AREA)
  • Plasma & Fusion (AREA)
  • General Engineering & Computer Science (AREA)
  • High Energy & Nuclear Physics (AREA)
  • Monitoring And Testing Of Nuclear Reactors (AREA)
  • Heat-Exchange Devices With Radiators And Conduit Assemblies (AREA)
  • Physical Or Chemical Processes And Apparatus (AREA)
  • Gasket Seals (AREA)
US835117A 1968-07-02 1969-06-20 Spacer grid for nuclear reactor fuel element assembly Expired - Lifetime US3674637A (en)

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
FR157536 1968-07-02

Publications (1)

Publication Number Publication Date
US3674637A true US3674637A (en) 1972-07-04

Family

ID=8651975

Family Applications (1)

Application Number Title Priority Date Filing Date
US835117A Expired - Lifetime US3674637A (en) 1968-07-02 1969-06-20 Spacer grid for nuclear reactor fuel element assembly

Country Status (13)

Country Link
US (1) US3674637A (es)
JP (1) JPS5037357B1 (es)
BE (1) BE734559A (es)
CA (1) CA920725A (es)
CH (1) CH509643A (es)
ES (1) ES368995A1 (es)
FR (1) FR1584335A (es)
GB (1) GB1204657A (es)
IL (1) IL32451A (es)
LU (1) LU58951A1 (es)
NL (1) NL163655C (es)
RO (1) RO55819A (es)
SE (1) SE341738B (es)

Cited By (12)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3833471A (en) * 1971-07-07 1974-09-03 Atomic Energy Authority Uk Nuclear reactor fuel element grid
US4058436A (en) * 1975-12-05 1977-11-15 Combustion Engineering Inc. Nuclear reactor seismic fuel assembly grid
US4059483A (en) * 1975-12-05 1977-11-22 Combustion Engineering, Inc. Nuclear fuel assembly seismic amplitude limiter
DE2755914A1 (de) * 1976-12-23 1978-06-29 Westinghouse Electric Corp Haltegitter fuer kernbrennelemente
US4124443A (en) * 1973-10-09 1978-11-07 Kraftwerk Union Aktiengesellschaft Nuclear fuel-rod assembly support structure
US4240876A (en) * 1977-05-13 1980-12-23 Commissariat A L'energie Atomique Nuclear fuel assembly
US5371769A (en) * 1992-07-10 1994-12-06 Mitsubishi Nuclear Fuel Co. Fuel rod support grids for fuel assembly
US20050109494A1 (en) * 2003-11-25 2005-05-26 Williams George J. Heat exchanger tube support
US20130301791A1 (en) * 2012-04-17 2013-11-14 Babcock & Wilcox Mpower Inc Pulse arc welding of spacer grids to guide tubes
WO2014152851A3 (en) * 2013-03-14 2015-10-29 Babcock & Wilcox Mpower, Inc. Spacer grid welding fixtrue
US20180286524A1 (en) * 2017-03-31 2018-10-04 Westinghouse Electric Company Llc Spacer Grid Using Tubular Cells With Mixing Vanes
WO2021055806A1 (en) * 2019-09-20 2021-03-25 Bwxt Nuclear Energy, Inc. Nuclear reactor plenum plate standoff spools

Families Citing this family (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3791466A (en) * 1969-05-19 1974-02-12 Westinghouse Electric Corp Low parasitic capture fuel assembly structure
FR2088009B1 (es) * 1970-05-06 1973-11-16 Commissariat Energie Atomique
US4135972A (en) * 1976-03-29 1979-01-23 Combustion Engineering, Inc. Nuclear reactor spacer assembly
FR2397042A1 (fr) * 1977-07-07 1979-02-02 Commissariat Energie Atomique Grille d'espacement pour un faisceau de crayons combustibles dans un assemblage de reacteur nucleaire
US4268356A (en) * 1978-07-14 1981-05-19 Westinghouse Electric Corp. Nuclear reactor fuel assembly grid
US4388269A (en) * 1980-11-21 1983-06-14 The Babcock & Wilcox Company Spacer grid corner gusset
US7149273B2 (en) * 2004-11-16 2006-12-12 Westinghouse Electric Co Llc Method of fabricating a nuclear reactor fuel assembly grid

Family Cites Families (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
FR1480965A (es) * 1965-05-25 1967-08-09
US3366546A (en) * 1965-12-02 1968-01-30 Combustion Eng Nuclear reactor

Cited By (19)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3833471A (en) * 1971-07-07 1974-09-03 Atomic Energy Authority Uk Nuclear reactor fuel element grid
US4124443A (en) * 1973-10-09 1978-11-07 Kraftwerk Union Aktiengesellschaft Nuclear fuel-rod assembly support structure
US4058436A (en) * 1975-12-05 1977-11-15 Combustion Engineering Inc. Nuclear reactor seismic fuel assembly grid
US4059483A (en) * 1975-12-05 1977-11-22 Combustion Engineering, Inc. Nuclear fuel assembly seismic amplitude limiter
DE2755914A1 (de) * 1976-12-23 1978-06-29 Westinghouse Electric Corp Haltegitter fuer kernbrennelemente
US4240876A (en) * 1977-05-13 1980-12-23 Commissariat A L'energie Atomique Nuclear fuel assembly
US5371769A (en) * 1992-07-10 1994-12-06 Mitsubishi Nuclear Fuel Co. Fuel rod support grids for fuel assembly
US7028765B2 (en) * 2003-11-25 2006-04-18 Trico Non-Ferrous Metal Products, Inc. Heat exchanger tube support
US20050109494A1 (en) * 2003-11-25 2005-05-26 Williams George J. Heat exchanger tube support
US20130301791A1 (en) * 2012-04-17 2013-11-14 Babcock & Wilcox Mpower Inc Pulse arc welding of spacer grids to guide tubes
WO2014152851A3 (en) * 2013-03-14 2015-10-29 Babcock & Wilcox Mpower, Inc. Spacer grid welding fixtrue
US10759007B2 (en) 2013-03-14 2020-09-01 Bwxt Mpower, Inc. Spacer grid welding fixture
US11338398B2 (en) 2013-03-14 2022-05-24 Bwxt Mpower, Inc. Spacer grid welding fixture
US11738416B2 (en) 2013-03-14 2023-08-29 Bwxt Mpower, Inc. Spacer grid welding fixture
US20180286524A1 (en) * 2017-03-31 2018-10-04 Westinghouse Electric Company Llc Spacer Grid Using Tubular Cells With Mixing Vanes
US10818402B2 (en) * 2017-03-31 2020-10-27 Westinghouse Electric Company Llc Spacer grid using tubular cells with mixing vanes
US11942230B2 (en) 2017-03-31 2024-03-26 Westinghouse Electric Company Llc Spacer grid using tubular cells
WO2021055806A1 (en) * 2019-09-20 2021-03-25 Bwxt Nuclear Energy, Inc. Nuclear reactor plenum plate standoff spools
US11724830B2 (en) 2019-09-20 2023-08-15 Bwxt Nuclear Energy, Inc. Plenum plate standoff spools for separating a pair of plenum plates in a nuclear reactor

Also Published As

Publication number Publication date
NL6909716A (es) 1970-01-06
GB1204657A (en) 1970-09-09
CH509643A (fr) 1971-06-30
NL163655C (nl) 1980-09-15
IL32451A (en) 1972-04-27
RO55819A (es) 1973-11-20
FR1584335A (es) 1969-12-19
CA920725A (en) 1973-02-06
ES368995A1 (es) 1972-03-16
LU58951A1 (es) 1969-11-12
DE1933319B2 (de) 1972-01-20
IL32451A0 (en) 1969-09-25
NL163655B (nl) 1980-04-15
BE734559A (es) 1969-11-17
SE341738B (es) 1972-01-10
DE1933319A1 (de) 1970-04-09
JPS5037357B1 (es) 1975-12-02

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